鈣鈦礦為近年來太陽能電池發展最受熱門的研究材料，鈣鈦礦太陽能電池的轉換效率在短短幾年內已經提升至25.7%，但鈣鈦礦易受水氣影響而裂解，仍需改善元件的環境穩定性。二維鈣鈦礦材料具有良好的耐熱性及耐濕性使許多團隊投入研究，但二維鈣鈦礦擁有較大的能隙，使元件的轉換效率並不理想。為了保留三維鈣鈦礦良好的光伏性能以及二維結構的高穩定性，有團隊將大尺寸陽離子疊加於三維鈣鈦礦上，在三維結構上成形成一層薄薄的二維結構，藉此改善元件的環境穩定性。
本研究以FA0.9Cs0.1PbI3三維鈣鈦礦為基底，選用Phenylammonium (PA+)、Phenylethylammonium (PEA+)及1,4-Benzene diammonium (BD2+)三種苯基結構的陽離子疊加於三維鈣鈦礦上進行探討，可比較不同鍊長的單胺基陽離子，及單、雙頭氨基陽離子對鈣鈦礦薄膜表面的影響，並分析不同陽離子對鈣鈦礦電池光伏性能及環境穩定性的影響。研究發現適量的PA+和PEA+單胺基陽離子能夠改善鈣鈦礦的表面鈍化、對薄膜表面修飾，並且提升元件效率、改善元件的穩定性，而過高濃度會使界面的傳輸電阻增加，反而使元件效能降低。雙頭氨基的BDI的溶解度低，因此分子容易析出，造成薄膜品質下降，使元件效率及穩定性不佳。
PA+和PEA+單胺基陽離子皆能改善薄膜品質，但僅有PEAI溶液在表面形成二維結構，而PA+則無，研究發現高濃度的PAI疊加於三維鈣鈦礦上會有新結構形成，推斷PA+陽離子尺寸大小為A位置的鈣鈦礦可以形成二維結構，但形成機率較小。

Recently, the perovskite solar cells(PSC) have achieved 25.7% high efficiency. However, the stability of the perovskite is still a big issue. Many research have applied several kinds of large-size organic cations on the surface of 3D perovskite films to form thin 2D perovskite layers, and obtain high-efficiency PSC with an ensured device stability. Here, we choose a series of phenyl ammonium cations likes Phenylammonium(PA+), Phenylethylammonium (PEA+) and 1,4-Benzene diammonium(BD2+), to analyze the effect of different cations on the surface of FA0.9Cs0.1PbI3 perovskite films. Both PA+ and PEA+ monoamine cations can modify the surface of the film, and thus improve the efficiency and stability of the device. The solubility of BDI in IPA is low, so molecules are easily precipitated in the solvent. Outcome to be the quality of the film is degraded, and the efficiency and stability of the device are not good as well. Moreover, PEAI will form 2D layer on the surface of 3D perovskite, while PAI will not. It is inferred that the size of the PA+ cation can form a 2D structure, but with the lower probability.

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